Trim indicator system

ABSTRACT

A system for indicating to the boat driver the trim angle at which his stern drive is set. The system incorporates a variable resistor which is enclosed in waterproof housing. The housing is mounted on the gimbal ring or yoke at the end of the shaft which is the horizontal tilt axis. The movable portion of the variable resistor is attached to the shaft which forms the horizontal tilt axis of a stern drive. In this manner, a signal proportional to the angle of tilt of the stern drive is created and can then be transferred to an indicator gauge. A trim limit switch having interchangeable parts with the variable resistor can also be mounted on the other end of the horizontal tilt axis and connected to the power trim system to limit the angular trim position of the stern drive.

United States Patent Schmiedel Feb. 15, 1972 {54] TRIM INDICATOR SYSTEMPrimary Examiner-Milton Buchler Assistant ExaminerCarl A. Rutledge [72]Inventor. Robert C. Schmiedel, Oshkosh, Wis. Anomey Roy T M om 8 cry[73] Assignee: Brunswick Corporation, Chicago, Ill.

57 [22] Filed: Oct. 5, 1970 l 1 ABSTRACT App]. No.: 78,046

Bratt et a]. ..244/76 R A system for indicating to the boat driver thetrim angle at which his stem drive is set. The system incorporates avariable resistor which is enclosed in waterproof housing. The housingis mounted on the girnbal ring or yoke at the end of the shaft which isthe horizontal tilt axis. The movable portion of the variable resistoris attached to the shaft. which forms the horizontal tilt axis of astern drive. in this manner, a signal proportional to the angle of tiltof the stern drive is created and can then be transferred to anindicator gauge. A trim limit switch having interchangeable parts withthe variable resistor can also be mounted on the other end of thehorizontal tilt axis and connected to the power trim system to limit theangular trim position of the stern drive.

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ROBERT C. SCHM/[DEL BY W ATTORNEY TRIM INDICATOR SYSTEM BACKGROUND OFTHE INVENTION This invention pertains to the field of instrumentationfor marine devices. More particularly, it relates to instrumentationsystems for indicating the angular position of an outboard drive unit.

Instrumentation for this purpose has long been known in the marinefield. One of the more well-known systems for use with a stern driveutilizes a separate hydraulic piston and cylinder in the hydraulic powertrim circuitry of the stern drive. Shielded push-pull cables wereconnected to the hydraulic cylinder to establish a mechanical connectionbetween the cylinder and an indicator gauge located in the instrumentpanel of the boat. The problems with such systems were twofold. First,the mechanical linkages involved were expensive and susceptible tobreakage. Second, errors were introduced due to both the backlash in themechanical system and the indirect reading from the hydraulic cylinderrather than directly from the drive unit.

BRIEF SUMMARY OF THE INVENTION In this invention an electrical system isutilized to indicate the trim position of the outboard drive unit. Sucha system could also be used on the steering axis to indicate thesteering position of the unit. This system includes a source of power orbattery and an electrical indicator gauge. A variable resistor assemblyis interposed between two members of the marine drive which pivot withrespect to each other when the outboard drive unit is tilted on itshorizontal axis. The drive unit could be an outboard motor or sterndrive. Said two members could be on an axis coincident with the tiltaxis or they could be on one of the shock absorber axes. In itspreferred embodiment, the resistor assembly is interposed between thegimbal ring and the outboard drive unit of a stern drive at thehorizontal tilt axis. The assembly is sealed in a housing which in turnis filled with a potting compound to aid in isolating the resistorassembly parts from the surrounding atmosphere. This is essential sincethe tilt axis is often under water. In this manner a repeatable directsignal is created in accordance with the angular position of the driveunit.

A limit switch assembly having parts interchangeable with the variableresistor assembly is mounted on the opposite end of the horizontal tiltaxis and also is interposed between the gimbal ring and the outboarddrive unit. The limit switch is electrically interconnected between asource of power and a hydraulic system to disconnect the hydraulicsystem when the outboard drive unit has reached its extreme outwarddriving position.

DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a schematic top plan view of a boat showing the electricalsystem.

FIG. 2 is a partial rear elevational view partially in section of astern drive with the assembly of this invention installed.

FIG. 3 is a side elevational view of a stern drive in three positions.

FIG. 4 is a side elevational view of a portion of a stern drive uponwhich a variable resistor assembly can be mounted.

FIG. 5 is a top plan view of the variable resistor assembly with coverremoved.

FIG. 6 is a top plan view of the limit switch with cover and rotorremoved.

FIG. 7 is a top plan view of the variable resistor assembly mounted on astern drive.

FIG. 8 is a sectional view taken along lines 88 of FIG. 7.

FIG. 9 is a bottom plan view of the variable resistor assembly.

FIG. 10 is a bottom plan view of the variable resistor assembly cover.

DETAILED DESCRIPTION OF THE INVENTION Referring generally to FIGS. 2-4,there is shown a marine drive mounted on the transom 10 of a boat 11.The marine drive includes a transom mounting assembly 12 and an outboarddrive unit I4 which is shown as a stern drive, but could also be anoutboard motor. The drive unit 14 is carried on the mounting assembly 12on a horizontal mounting axis 16 to tilt to any position within theextremes indicated by A and C in FIG. 3. A hydraulic system (describedspecifically in US. Pat. No. 3,434,448) utilizing a pump 18 (FIG. I) anda pair of shock absorbers 19, 20 (FIGS. 2 and 3) serves as a means forpositioning the drive unit at any desired tilt position. The drive unit14 includes two outwardly extending horizontal shafts or members 22 and23 (not shown) which are rotatably mounted in a gimbal ring or member25. The gimbal ring 25 is mounted on the transom mounting assembly 12for pivoting about a generally vertical axis 27 to steer the boat 11 inany desired direction.

In operation it is desirable to tuck" the drive unit I4 under the boattoward position A when starting the boat 11 to aid it in planing.However, when the boat I I is on plane, it is desirable to repositionthe drive unit 14 further outward for maximum efficiency and speed. Oncethe operator establishes the optimum angle for given conditions, thisinvention provides a means for repeating those conditions. However,there is a maximum outward angle indicated by position B, above which ithas been found unsafe to operate the drive unit 14 under power. Thus, itis desirable to limit the angle of the drive unit 14 to position B whenoperating under full power. A device for so limiting is provided in thisinvention. This invention further provides means for overriding thelimit to move the unit 14 to the extreme upward position C fortrailering or low-power operation.

Referring again to FIG. 1 and FIG. 2 there is shown a variable resistorassembly 30 mounted on the right side of the gimbal ring 25. Theassembly 30 is mounted on a pivot axis on which two members rotate withrespect to each other when the unit I4 is tilted. Such an axis is shownas coincident with the mounting axis 16 and the relatively rotatingmembers are the shaft 22 and the gimbal ring 25. However, the pivot axiscould readily be at either end of the shock absorbers l9 and 20 asindicated by 33 and 34. The assembly 30 includes two variable resistorelements or cards 31 and 32 which are fixed in a housing 38 which inturn isfixed to the gimbal ring or member 25 by the mounting screws 39.The assembly 30 further includes a contact rotor 43 with a contact rotorarm 68 fixed thereto having contacts 35 and 36 at each end thereof incontact with the resistor cards 31 and 32 respectively. The rotor arm 68is preferably made of spring steel to assure continued contact. Therotor 43 is fixed to the end of the shaft 23 to rotate therewith in amanner which will be explained later. One end 37 of the card 31 isconnected to the ground terminal 51 of the battery 52 through line 75,connector 40 and line 41. The diametrically opposite end 42 of the card32 is connected to one terminal 48 of the trim indicator gauge 47through line 45, connector 44 and line 46. The other terminal 50 of thetrim indicator 47 is connected to the positive side 54 of the batterythrough the key switch (not shown).

The rotor 43 on the variable resistor assembly 30 is shown in FIG. 1,FIG. 5, and FIG. 9 in its zero resistance" position. At this positionthe drive unit I4 is in position A. Zero resistance is accomplished byusing an end connector 55 which has a circular cutout 56 and crimpingthe inside end 57 of the connector 55 to establish contact at thatpoint. Thus, no resistance is detected by the trim indicator gauge 47.As the drive unit 14 at position A is raised toward position B, therotor 43 is rotated clockwise (in FIG. 1 and 5) to increase theresistance between the gauge 47 and ground terminal 51 of battery 52.The trim indicator gauge 47 then indicates to the operator the positionof the drive unit 14. A linear variable resistor card 31 and 32 is usedsince it can be purchased inexpensively and clipped from a continuousrole. However, since the rotor 43 moves in a circular manner over thelinear card 31 and 32, the resistance detected is not in proportion tothe angular position of the drive unit 14. Further, it has been founddesirable for the gauge 47 to read a much greater angular change thanthe unit 14 moves when going from position A to position B and a lesschange when the unit 14 goes from position B to position C. Suchfeatures can be designed into gauge movements of purchased gauges bymeans well known in the art.

Referring now to the limit switch side of the circuit (left side of FIG.1), there is shown a limit switch assembly 60 having a housing 61 whichis fixed to the left side of the member or gimbal ring 25 (FIG. 2). Thelimit switch assembly 60 includes two contact stips 63 and 64 fixed inthe housing 61 and a contact rotor 66 fixed to the shaft 23 (not shown)to rotate therewith in a manner which will be described below. Again, inFIG. 1, the rotor 66 is shown in the position it would be when the unitis in position A. As the unit 14 is raised, the rotor 66 rotates in adirection until contact has broken.

In operation when the operator wishes to raise the drive unit 14 fromits lower extreme position A, he pushes the middle or trim-up button 67.This closes the circuit through the battery ground 51, pump 18, line 75,connector 76, line 77, contact 63, rotor 66, contact 64, line 78,connector 80, line 82, push button 67, and the positive terminal 54 ofbattery 52. If the unit 14 reaches its extreme upward driving positionB, the rotor 66 breaks the circuit by going off the contacts 63 and 64.If the operator wishes to position the unit 14 further up fortrailering, he can continue to raise the unit 14 by pushing both buttons67 and 87. In this manner the circuit will be closed from the batteryground 51, through the pump 18, line 86, button 87, button 67, and thepositive terminal 54 of the battery 52. In this manner the limit switchportion of the circuit is overridden.

If it is desired to lower the unit, the lower button 90 is pushedclosing the circuit between the ground 51, the pump 18, the line 91, thebutton 90 and the positive terminal 54 of the battery 52. Although thesystem is operable as shown and described, in practice it has been foundadvantageous to utilize a slave relay" circuit at the hydraulic pump 18.In this manner the full current flowing through the hydraulic pump 18does not flow through the pushbutton switches 67, 87, and/or 90.

Although the variable resistor assembly 30 and limit switch assembly 60are shown in the preferred embodiment of this invention as beinginterposed between the gimbal ring 25 and the drive unit 14 at themounting axis 16, it should be noted that any axis may be used in whichtwo members relatively rotate upon pivot of the drive unit 14. Thus,referring to FIGS. 24, either of the axes 33 and 34 of the shockabsorbers 19, 20 could be used. This would introduce errors in thesystem since the shock absorbers 19 and 20 do not rotate the same as thedrive unit 14 does on its mounting axis 16. However, the positioningwould still be repeatable from the indicator 47 once the operatorestablishes his optimum operator conditions.

FIGS. -10 show further details of the variable resistor and limit switchassemblies. These assemblies are exactly alike a use interchangeableparts with the exception of the resistor assembly using resistor cards31 and 32 (FIG. 5) and the limit switch assembly using contact strips 63and 64 (FIG. 6). The variable resistor assembly 30 is shown and will bedescribed in detail. The resistor assembly 30 includes a housing 38 forhousing the rotor 43 and resistor cards 31 and 32. The housing 38 has aspace 101 therein formed in the housing cover 104 for freedom ofmovement of the rotor 43. The housing also includes a sealing gasket 103between the base 102 and the cover 104. The cover 104 and gasket 103 arefirmly secured to the base by eight screws. Three screws 106 beinginserted through the cover 104 and gasket and into the base (FIG. 7) andfour screws 107 being inserted through the base and into the cover (FIG.9). One of the screws 105 shown in FIG. 7 serves an additional specialpurpose which will be explained later.

The rotor 43 has a shaft 108 with a circular first portion 109 carriedrotationally in the housing base 102, and a nonround portion 110 whichmates into a nonround hole 111 in the end face 112 of the horizontalshaft 22. The nonround portion 110 is shown as hexagonal and in itspreferred embodiment includes outwardly extending ribs 113 at eachcorner of the hexagon to provide an interference fit into the hole 111in the shaft 22. The hole 111 in the shaft 22 is preferably also ahexagon to provide initial adjustment of the assembly 30. The firstportion 109 of the shaft has a pair of seals 98, 99 thereon to seal theshaft 108 within the housing base 102. To further seal the assembly 30,a heated potting compound 118 (such as that known by the trademarkBiwax) is injected through the hole 117, into space 101, and slot 115until it flows out the hole 114. The screws 105 and 117 are theninserted sealing the assembly 30 in a watertight manner. The rotor 30also includes a head portion 120 within the housing upon which thecontact arm 68 is connected at its center. The head portion 120 iscircular in shape to move freely through the potting compound 1 l8 andreduce the shear forces on the contact arm 68 upon rapid movement of theoutboard drive unit 14 such as when striking an underwater object. Thehousing cover 104 has a space 101 formed therein to provide the space inwhich the rotor 43 is carried. The head 120 is designed to closely fitunder the housing cover 104 such that when the shaft portion 110 isforced into the end hole 111 of the horizontal shaft 22, the cover 104forces the shaft 110 into the mating hole 111. The rotor arm 68 is aspring steel stamping to assure continuous contact no matter where therotor 43 is positioned axially in the space 10].

Referring to FIG. 9 there is a small mark formed on the base 102 of thehousing 38 and a corresponding mark 126 formed on the end of the shaftportion 1 10. At assembly these two marks 125 and 126 are aligned asshown in FIG. 9 to position the rotor 43 in the zero resistance positionshown in FIG. 5. When the assembly 30 is installed, the drive unit 14 isin its downward position A. The slots 127 and 128 for mounting screws 39then allow freedom to insert the shaft 108 into the hole 111 and providethe preadjustment of zero resistance corresponding with full downposition A of the drive unit 14. Further, two pairs of mounting holesare provided to give the installer a choice at installation.

Thus, at installation, the unit 14 is positioned in position A, themarks 125 and 126 on the variable resistor assembly 30 are aligned, andthe shaft 110 is forced into hole 111 by the installers hand. Thehousing 38 is then turned until the indicator 47 reads position A.Finally, the screws 39 are inserted to complete the mounting. The markson the limit switch assembly 60 are then aligned and it is similarlymounted. This provides means for initial adjustment of said assembly 30at installation.

What is claimed is:

1. In a marine drive having an outboard drive unit carried on thetransom of a boat for angular movement about a mounting axis andincluding members connected together at a pivot axis such that there isrelative rotation between said members upon angular movement of saidunit about said mounting axis, the improvement comprising:

a. a source of electrical energy;

b. an electrical indicator for indicating the angular position of saidunit about said mounting axis, one side of said indicator beingconnected to one side of said source; and

c. a variable resistor assembly interposed between two of said membersat said pivot axis such that the resistance of said assembly is variedin accordance with the angular position of said unit about said mountingaxis, said resistor assembly being interconnected between the other sideof said source and the other side of said indicator.

2. The improvement as in claim 1 wherein said pivot axis is generallyparallel to said mounting axis.

3. The improvement as in claim 1 wherein said pivot is coincidental withsaid mounting axis.

4. The improvement of claim 1 wherein said variable resistor assemblyincludes a housing fixed to one of said members by means to provideinitial adjustment of said assembly at installation.

5. The improvement of claim 1 wherein the mounting axis is a horizontaltilt axis generally perpendicular to the fore-andaft centerline of theboat.

6. The improvement as in claim 1 further comprising:

a. means for positioning said drive unit about said mounting axis at anyangular position within a given angular range; and

b. a limit switch assembly interposed between a pair of said members atsaid pivot axis for disconnecting said means for positioning when theunit reaches a maximum predetermined angular position.

7. The improvement of claim 6 wherein said limit switch assemblycomprises:

a. a housing fixed to one of a pair of said members and having a spacetherein;

b. a contact rotor rotationally carried in said switch housing and fixedto the other of said pair of members, said rotor having twodiametrically opposite contacts; and

c. a pair of contact cards mounted in said switch housing ondiametrically opposite sides of said switch rotor for contact by therespective switch rotor contacts, said cards being connected to themeans for positioning to provide disconnecting.

8. The improvement of claim 7 wherein said resistor card includes aconnector on one end having a generally circular cu tout to provide azero resistance for said contact rotor.

9. The improvement of claim 6 wherein said limit switch assembly andsaid variable resistor assembly are on opposite ends of said pivot axis.

10. The improvement as claimed in claim 6 wherein said cariable resistorassembly and said limit switch assembly contained interchangeable parts.

11. The improvement as claimed in claim 1 wherein said variable resistorassembly comprises:

a. a housing fixed to one of said two members and having a spacetherein;

b. a contact rotor rotationally carried in said housing and fixed to theother of said two members, said rotor having two diametrically oppositecontacts; and

c. a pair of variable resistor cards mounted in said housing ondiametrically opposite sides of said rotor for contact by the respectivecontacts, one of said cards being connected to the source and the otherto the meter.

12. The improvement of claim 11 further comprising:

a. means for positioning said drive unit about said mounting axis at anyangular position within a given angular range; and

b. a limit switch assembly interposed between a pair of said members atsaid pivot axis for disconnecting said means for positioning when theunit reaches a maximum predetermined angular position.

13. The improvement of claim 11 wherein said limit switch assemblycomprises:

a. a housing fixed to one of said pair of members and having a spacetherein;

b. a contact rotor rotationally carried in said housing and fixed to theother of said pair of members, said rotor having two diametricallyopposite contacts; and

c. a pair of contact cards mounted in said housing on diametricallyopposite sides of said rotor for contact by the respective rotorcontacts, said cards being connected to the means for positioning toprovide disconnecting.

14. The improvement of claim 13 wherein the space in said housing issealed and contains potting compound therein.

15. The improvement of claim 14 wherein said rotor includes a circularhead in said housing for minimal resistance to movement in said pottingcompound and wherein said contact rotor is supported on said head.

16. The improvement of claim 13 wherein the housing and contact rotor ofthe variable resistor assembly are respectively interchangeable with thehousing and contact rotor of the limit switch assembly.

17. The improvement of claim 11 wherein said other member includes ashaft on said axis rotationally mounted in said one member, said shafthaving an end face therein exposed outwardly with a nonround holetherein and said rotor further comprises:

a. a second shaft formed to fit in the hole in said shaft; and

b. a head portion fitting closely in the space in said housing such thatwhen said housing is fixed to said one member, said second shaft isprevented from escaping from the hole in said first shaft.

18. The improvement of claim 17 wherein said hole is polygonal in shapeand said second shaft is also polygonal in shape and includes outwardlyextending ribs at each corner of the polygon for an interference fitinto said hole.

19. The improvement of claim 11 wherein the space in said housing issealed and contains potting compound therein.

20. The improvement of claim l4 wherein said rotor includes a circularhead in said housing for minimal resistance to movement in said pottingcompound and wherein said contact rotor is supported on said head.

21. In a marine drive having an outboard drive unit carried by amounting assembly on the transom of a boat on a horizontal axisperpendicular to the fore-and-aft boat centerline, the improvementcomprising:

a. a hydraulic system for positioning said drive unit about said axis atany angular position within a predetermined angular range;

. an indicator mounted within the boat for indicating the angularposition of said drive unit;

c. a source of electrical power having one terminal connected to saidgauge and a second terminal connected to said hydraulic system;

. a variable resistor assembly interposed between a portion of saidmounting assembly and a portion of said drive unit at one end of saidaxis such that the resistance of said assembly varies in accordance withthe angular position of said unit, said assembly being electricallyinterconnected between the other terminal of said battery and theindicator; and

e. a limit switch interposed between a portion of said mounting assemblyand a portion of said drive unit at the other end of said axis andelectrically interconnected between said source and said hydraulicsystem.

1. In a marine drive having an outboard drive unit carried on thetransom of a boat for angular movement about a mounting axis andincluding members connected together at a pivot axis such that there isrelative rotation between said members upon angular movement of saidunit about said mounting axis, the improvement comprising: a. a sourceof electrical energy; b. an electrical indicator for indicating theangular position of said unit about said mounting axis, one side of saidindicator being connected to one side of said source; and c. a variableresistor assembly interposed between two of said members at said pivotaxis such that the resistance of said assembly is varied in accordancewith the angular position of said unit about said mounting axis, saidresistor assembly being interconnected between the other side of saidsource and the other side of said indicator.
 2. The improvement as inclaim 1 wherein said pivot axis is generally parallel to said mountingaxis.
 3. The improvement as in claim 1 wherein said pivot iscoincidental with said mounting axis.
 4. The improvement of claim 1wherein said variable resistor assembly includes a housing fixed to oneof said members by means to provide initial adjustment of said assemblyat installation.
 5. The improvement of claim 1 wherein the mounting axisis a horizontal tilt axis generally perpendicular to the fore-and-aftcenterline of the boat.
 6. The improvement as in claim 1 furthercomprising: a. means for positioning said drive unit about said mountingaxis at any angular position within a given angular range; and b. alimit switch assembly interposed between a pair of said members at saidpivot axis for disconnecting said means for positioning when the unitreaches a maximum predetermined angular position.
 7. The improvement ofclaim 6 wherein said limit switch assembly comprises: a. a housing fixedto one of a pair of said members and having a space therein; b. acontact rotor rotationally carried in said switch housing and fixed tothe other of said pair of members, said rotor having two diametricallyopposite contacts; and c. a pair of contact cards mounted in said switchhousing on diametrically opposite sides of said switch rotor for contactby the respective switch rotor contacts, said cards being connected tothe means for positioning to provide disconnecting.
 8. The improvementof claim 7 wherein said resistor card includes a connector on one endhaving a generally circular cutout to provide a zero resistance for saidcontact rotor.
 9. The improvement of claim 6 wherein said limit switchassembly and said variable resistor assembly are on opposite ends ofsaid pivot axis.
 10. The improvement as claimed in claim 6 wherein saidcariable resistor assembly and said limit switch assembly containedinterchangeable parts.
 11. The improvement as claimed in claim 1 whereinsaid variable resistor assembly comprises: a. a housing fixed to one ofsaid two members and having a space therein; b. a contact rotorrotationally carried in said housing and fixed to the other of said twomembers, said rotor having two diametrically opposite contacts; and c. apair of variable resistor cards mounted in said housing on diametricallyopposite sides of said rotor for contact by the respective contacts, oneof said cards being connected to the source and the other to the meter.12. The improvement of claim 11 further comprising: a. means forpositioning said drive unit about said mounting axis at any angularposition within a given angular range; and b. a limit switch assemblyinterposed between a pair of said members at said pivot axis fordisconnecting said means for positioning when the unit reaches a maximumpredetermined angular position.
 13. The improvement of claim 11 whereinsaid limit switch assembly comprises: a. a housing fixed to one of saidpair of members and having a space therein; b. a contact rotorrotationally carried in said housing and fixed to the other of said pairof members, said rotor having two diametrically opposite contacts; andc. a pair of contact cards mounted in said housing on diametricallyopposite sides of said rotor for contact by the respective rotorcontacts, said cards being connected to the means for positioning toprovide disconnecting.
 14. The improvement of claim 13 wherein the spacein said housing is sealed and contains potting compound therein.
 15. Theimprovement of claim 14 wherein said rotor includes a circular head insaid housing for minimal resistance to movement in said potting compoundand wherein said contact rotor is supported on said head.
 16. Theimprovement of claim 13 wherein the housing and contact rotor of thevariable resistor assembly are respectively interchangeable with thehousing and contact rotor of the limit switch assembly.
 17. Theimprovement of claim 11 wherein said other member includes a shaft onsaid axis rotationally mounted in said one member, said shaft having anend face therein exposed outwardly with a nonround hole therein and saidrotor further comprises: a. a second shaft formed to fit in the hole insaid shaft; and b. a head portion fitting closely in the space in saidhousing such that when said housing is fixed to said one member, saidsecond shaft is prevented from escaping from the hole in said firstshaft.
 18. The improvement of claim 17 wherein said hole is polygonal inshape and said second shaft is also polygonal in shape and includesoutwardly extending ribs at each corner of the polygon for aninterference fit into said hole.
 19. The improvement of claim 11 whereinthe space in said housing is sealed and contains potting compoundtherein.
 20. The improvement of claim 14 wherein said rotor includes acircular head in said housing for minimal resistance to movement in saidpotting compound and wherein said contact rotor is supported on saidhead.
 21. In a marine drive having an outboard drive unit carried by amounting assembly on the transom of a boat on a horizontal axisperpendicular to the fore-and-aft boat centerline, the improvementcomprising: a. a hydraulic system for positioning said drive unit aboutsaid axis at any angular position within a predetermined angular range;b. an indicator mounted within the boat for indicating the angularposition of said drive unit; c. a source of electrical power having oneterminal connected to said gauge and a second terminal connected to saidhydraulic system; d. a variable resistor assembly interposed between aportion of said mounting assembly and a portion of said drive unit atone end of said axis such that the resistance of said assembly varies inaccordance with the angular position of said unit, said assembly beingelectrically interconnected between the other terminal of said batteryand the indicator; and e. a limit switch interposed between a portion ofsaid mounting assembly and a portion of said drive unit at the other endof said axis and electrically interconnected between said source andsaid hydraulic system.